1. Field of the Disclosure
This disclosure relates to an organic electro-luminescent display device, and more particularly to an organic electro-luminescent display device of dual panel type adapted to ensure the reliability and to improve the lifespan and an electric contact characteristic between a drive element and an organic light emission element.
2. Description of the Related Art
Display devices have been developed along with the development of information communication and have became a modern-day necessity. Of the display devices, organic electro-luminescence display (OLED) devices can be light and slim since they do not need the backlight units required for liquid crystal display devices. Also, the OLED devices can be manufactured through a simple process and thus have competitive prices. Moreover, the OLED devices have a low voltage drive, a high luminous efficiency, and a wide viewing angle. In view of these points, the OLED devices have received a growing amount of attention as one of next-generation display devices.
The OLED devices fundamentally include an organic light emission diode element consisting of an anode electrode, a cathode electrode, and an organic light emission layer interposed between the anode and cathode electrodes. The organic light emission diode element uses a luminous principle which involves combining excitation leptons (or particles) such as a free hole and an electron. The combination of a free hole and an electron allows them to transit from a state of instability to a stable status, and in doing so, emit light. In other words, the organic light emission diode element generates free holes in the anode electrode and free electrons in the cathode electrode so that the free holes and electrons from the anode and cathode electrodes can be recombined with each other in the organic light emission layer, thereby emitting light.
The organic light emission layer easily deteriorates under exposure of either oxygen or moisture causing defects such as dark spots and dark pixels in the OLED device. The dark spots are viewed by users because some pixels displaying an image are not luminous. The dark pixel means that at least one among a plurality of pixels is not luminous.
To address these defects, an OLED device has been proposed which includes organic light emission diode elements sealed by both a seal substrate and a UV (ultra violet ray) hardening resin and are thus shielded from the external environment. However, the seal substrate and UV hardening resin cannot completely seal the organic light emission diode elements. In other words, the seal substrate and UV hardening resin do not substantially shield either external moisture or oxygen from intruding into the organic light emission diode elements. Accordingly, the organic light emission diode elements may deteriorate over time.
Another alternative has been proposed which inserts a gather into an OLED device. This gather eliminates at least partially eliminates intruding moisture and oxygen, thus ensuring the reliability and improving the lifespan of the device. It is spatially difficult to include the gather in a dual panel type OLED device including driver elements and organic light emission diode elements which are formed in substrates. Accordingly, the deterioration of the organic light emission layer caused by moisture and/or oxygen is aggravated in the dual panel type OLED device.